I had a vibration when I drove my vehicle and it was suggested that before looking into things like alignment or other possible causes, that I should get my tires looked at and balanced. Turns out, the guys at Discount Tire wouldn't even balance them because the moment they looked at my tires - they saw a fist-sized bulge in one and the steel belt coming through on another. They showed me the problem, explained why a blowout is inevitable, the reasons why balancing would be futile and recommended immediate replacement.
The staff was very helpful, their explanations were to my level and the service was great. Granted, I did NOT expect to go in for a balancing job and to walk out with two new tires but it was certainly the right call.